I live one lot off the Columbia River and have a decent view of whatever’s going on from my living room window (right now, the fall salmon are coming through, so there are usually several optimists parked in the channel). Every couple of hours for the last few days a Bell has thundered almost directly overhead, then made a left turn and followed the river out into the Hanford Reach. The Reach is home of the Hanford Nuclear Reservation (and the NSA depicted on the sectional map), and from our house we can see 2 decommissioned plutonium breeder reactors and an active nuclear power plant. It isn’t as awful as it sounds–boating up on the Reach is pretty secluded, and the tight security has been a boon for wildlife (deer, elk, coyotes, and all kinds of birds).
The River makes a nice flyway, and during summer weekends we’ll often see a Cessna or ultralight flying low-level northbound. Since were’re up off the river by 50+ feet, low-level to the river means even with our rooftops most times. This Bell has been following the river too–low level, but much higher than most of the fixed wing traffic. Like most rivers, the Columbia is easy to navigate and relatively free of obstructions; unlike the surrounding terrain, it’s also nice and flat. On this section of the river there are multiple power line crossings within the 50 or so miles between Richland and Priest Rapids Dam. Most of them are massive transmission towers, like two on the southern-most stretch. The first, unlighted set is an unmistakable eyesore–three lines, with orange and white towers on the river bank, at a slightly narrow stretch in the river. The second though isn’t so obvious, even though the towers are painted and lighted, it’s a single span (albeit they are still transmission wires). At that point, the river separates into 2 channels that are 1000 feet wide. If a pilot were navigating right straight up the river, there’s a point where the 3 towers would be in sight but the wires themselves wouldn’t be visible. With such a wide span though, there is a point where the towers will drop out of his field of view and the wires won’t yet be visible. This is the danger zone–a distraction at this point and those towers can drop out of his short term memory. When he looks up again, there’s nothing in his field of view until the wires come into his resolution distance. By then it’s too late to maneuver around them.
The other tricky part about wires crossing a span like this is that they don’t stay put vertically. Not that this is advisable behavior, but these plank-drivers are flying low enough that they could just as easily fly under the wires as over. Wires aren’t constants though, and the altitude that allows you to clear the wires during the early morning outbound flight isn’t going to be the same as the altitude that helps you clear the wires on the afternoon return trip. Since the wires are metal, they expand as they heat up. This can be from ambient temperatures–since this is the desert, we can be near freezing on an autumn morning and up in the 90s during the daytime. Or the load on the wires can generate the heat. Cool weather, low load, and the wires at mid-span will be high relative to where they are when the day heats up and there’s a high load on the system. Both of these problems are compounded when the surrounding terrain (higher elevations, forest) or environment (haze or fog) makes the towers harder to see and the wires invisible. Yes, I have heard a plane fly by low-level on days where I can barely make out the other side of the river because of fog.
The solution is to not fly down with the wires. The higher you fly, the lower your chance of getting clothes-lined. Turns out the Bell that’s working out in the area is going by the callsign Enery 11, so I’m guessing they’re working those powerlines in the Reach. I’d hoped to get up to the airport to see the ship up close and find out what they’re doing, but my friend at Bergstrom Aircraft who usually gets me out on the ramp whenever there’s a helicopter based there is out on vacation this week. Might head up onto the reach tomorrow to see if I can get a glimpse.